In electric arc welding, a welding gun is a flexible, elongated element having a rear end connected to a wire feeder and a front end for a welding torch. The gun includes an elongated flexible conduit directing current and shielding gas from the wire feeder to the welding torch. Such a mechanism is employed for hand held welding and for robotic controlled welding in the trade.
The torch includes a contact tip through which the welding wire is directed from the wire feeder through the flexible tube to the welding operation. This tip is supported in a conductive cylindrical assembly receiving power from the wire feeder.
Shielding gas is directed from a diffuser in. the cylindrical assembly into a chamber defined by an outer nozzle through the nozzle into the area around the contact tip so the shielding gas forms a protective layer between the molten metal of the welding operation and atmosphere. All of these requirements of a torch require complex machined components at the end of the torch which substantially increases the cost and adversely affects the operability of the torch during the welding operation. Furthermore, the welding operation itself creates spatter, especially during short circuit conditions so the forward end of the torch including the contact tip and diffuser is subject to substantial deterioration over time caused by spatter together with the tremendous arc temperature involved in the welding operation.
Shielding gas is directed into the welding operation from diffuser orifices circumferentially spaced around the torch and directed ultimately to the contact tip at the welding operation. Consequently, torches have diffuser orifices for shielding gas; however, these orifices must be oriented to prevent unwanted cavitation. It has been found that these orifices should be as close as possible to the welding operation. Such closeness drastically increases the tendency for spatter to affect the laminar flow of shielding gas from the diffuser orifices.
Robotic assemblies are commonly used with welding guns. Previously, when robotic gun assemblies were dismantled, the down time was extensive because there was no quick and easy means to precisely reassemble the robotic gun. A previous example of a keyed alignment system for a welding torch used with a robotic gun assembly is shown in U.S. Pat. No. 5,451,117. A mounting arm which provides for various methods of changing position of the welding gun with respect to the robotic arm and the position of the gun with respect to its housing as well as providing easy disassembly of the gun from the robotic arm is described in co-pending application Ser. No. 11/178,819, filed on Jul. 11, 2005. Hex end structures for the torch end and welding wire feeder and are shown and described in co-pending application Ser. No. 11/268,085, filed on Nov. 7, 2005.
Furthermore, a welding gun which allows for various positions of the forward end and rear end of the gun is needed without complete disassembly of the gun. Accordingly, it is considered desirable to provide a welding gun which allows various positions of the welding gun with respect to the robotic assembly and with respect to the handle without completely disassembling either the gun or the robotic arm assembly. Also, providing a handle which allows for ease in assembly and disassembly of the welding gun as well as providing access to the internal components of the gun at either the welding torch end or wire feeder end is also desired.